Base points

K Davis

Member
The other day I went back to a project I started a month ago to do some additional work at the request of the client. I set the base on the control point I originally established (base point 990) which was in the design point list because I had deleted the job in the LS thinking I was finished back in May. I took some road shots and other shots I needed to calculate where to set 2 monuments. Later in the day I went back and set those monuments, so I had 2 base points (991 and 992) for the additional work.

While finishing the plat this morning I noticed that base points 991 and 992 did not constrain to the original base point 990. The CORS solution for base 991 is 8 inches east of 990 and was not moved back over to 990. The CORS solution for 991 was about a tenth west of 990 and was also not moved back to 990.

I've checked my other recent jobs and this did not happen on any of them.

I haven't changed any settings that I'm aware, but I am wondering how this happened?

The coordinate on the screenshot of the LS is 990.
 

Attachments

Michael Stazhkov

Developer
Staff member
5PLS
The other day I went back to a project I started a month ago to do some additional work at the request of the client. I set the base on the control point I originally established (base point 990) which was in the design point list because I had deleted the job in the LS thinking I was finished back in May. I took some road shots and other shots I needed to calculate where to set 2 monuments. Later in the day I went back and set those monuments, so I had 2 base points (991 and 992) for the additional work.

While finishing the plat this morning I noticed that base points 991 and 992 did not constrain to the original base point 990. The CORS solution for base 991 is 8 inches east of 990 and was not moved back over to 990. The CORS solution for 991 was about a tenth west of 990 and was also not moved back to 990.

I've checked my other recent jobs and this did not happen on any of them.

I haven't changed any settings that I'm aware, but I am wondering how this happened?

The coordinate on the screenshot of the LS is 990.
Hello, Davis. Did you record GNSS files on the points? Could you "Send Project to Support" (button in the "Projects" screen).
 

K Davis

Member
Is there a setting to have the post-DPOS base points not hold to the Cors solution but rather default to the coordinates I selected from the Design points list when starting the base on a known point?

After DPOS with a base point intended to hold on a coordinate selected from the Design point list there is no "KNOWN" option.


20190606a.png20190606b.png
 

Shawn Billings

Shawn Billings
5PLS
It treated your known point as an autonomous position. You can click auto to get back to your known point. I've seen this before and I think it has been resolved in newer unreleased versions.
 

Vladimir Prasolov

Well-Known Member
5PLS
Hi Devis,

1. If you want use DPOS for vector estimation please set "Base-Rover Processing only". It will prevent from base position overriding by CORS-based solution.

8965



2. If Base CORS Processing is done too early, it could be not enough data on CORS stations for such processing. It is take time to upload collected data for CORS stations for NGS services. It happened in your case. For example, please compare two reports for same station:

8966


When you processed your data it is only one CORS station data available.

3. I reDEPOS the points and calculate distances between 991 and 992:

Old DPOS 0.8016 ft:

8967


New DPOS 0.0995 ft :

8968


So I would recommend:

1. For good Base CORS processing wait as minimum one day (it is true for DPOS and OPUS too).

2. For Base-Rover Processing (to verify RTK solution) please use "Base-Rover Processing only in DPOS configuration.

See attachment for DPOS reports.
 

Attachments

Steve Douty

Active Member
It treated your known point as an autonomous position. You can click auto to get back to your known point. I've seen this before and I think it has been resolved in newer unreleased versions.
I have been stung a few times by this. I think I have learned my lesson. The DPOS report is confusing I believe that If I chose the base coordinate from a list (Survey or Design) that the final DPOS report should acknowledge that choice and report the differances to CORS and PPK; not hold the CORS.

Please consider this as a request for a revision.
 

Vladimir Prasolov

Well-Known Member
5PLS
I have been stung a few times by this. I think I have learned my lesson. The DPOS report is confusing I believe that If I chose the base coordinate from a list (Survey or Design) that the final DPOS report should acknowledge that choice and report the differances to CORS and PPK; not hold the CORS.

Please consider this as a request for a revision.
We think to add direct check box option to mark base position as Known on Setup Base screen.
 
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